Arrangement for grinding the inside walls of cylindrical containers



April 1, 1958 H. LIST ET AL 2,828,586

ARRANGEMENT FOR GRINDING THE INSIDE WALLS OF CYLINDRICAL CONTAINERSFiled June 28, 1956 ERNST GRANACHER ilniteti States Patent ARRANGEMENTFUR GRINDING THE INSIDE WALLS OF CYLINDRICAL CONTAINERS Heinz List andFriedrich Friisch, Pratteln, Switzerland, and Ernst Granacher,Sackingen, Germany, assignors to Buss A. G., Basel, SwitzerlandApplication June 28, 1956, Serial No. 594,514

Claims priority, application Switzerland June 29, 1955 1 Claim. (Cl.51-141) In the manufacture of chemical apparatus in particular, thenecessity arises for grinding the inside walls of cylindrical containersof all kind which are made of stainless steel, since thereby theresistibilty of the material against the corrosive action of thechemical substances is considerably increased.

To such end, the walls of drums and the like have so far been groundwith the aid of electrically operated and manually guided grindingmeans. The operator together with his grinding apparatus was positionedinside the drum and wearing a protective mask against the development ofdust, had to perform this operation in a tedious and time-c0nsumingmanner. Such grinding operation was expensive and even dangerous whencarried out without any protective mask. The resulting grinding patternwas irregular.

The present invention provides an arrangement for grinding the insidewalls of cylindrical containers which permits the above mentioneddisadvantages and drawbacks to be avoided. This arrangement ischaracterized by a grinding apparatus mounted on an arm whichautomatically performs a limited reciprocal movement.

A preferred embodiment of the invention is illustrated, by way ofexample, in the accompanying drawing, in which- Fig. 1 is a side view ofthe arrangement, and

Fig. 2 is a front view thereof.

The arrangement comprises a frame a with vertical guides b in which isguided a slide 0 being vertically adjustable by means of a spindle d. Inslide c is mounted a horizontal arm e which is reciprocated via avariable ratio gearing f, the speed of this arm and thus of the grindingoperation being variable. In the terminal positions of arm 2 themovement thereof is interrupted by limit switches g and dogs h which areadjustably mounted on the arm. This results in an automaticreciprocating movement of arm e.

On the forward end of arm e is disposed a grinding apparatus i of aconstruction known per se which is driven by an electric motor k.Grinding apparatus i and motor k are mounted on a cantilever linflexible bearings m, for example by using rubber sleeves. The pressureunder which the grinding tape 0, which is trained over a wheel n, isurged against the interior wall p of the drum, depends on the dead loadof apparatus i and motor k. This pressure may be still furtherincreased, also during the grinding operation, by angularly moving aboutits own axis the cantilever l on which are disposed the flexiblebearings m, by means of a handwheel q.

The drum wall is constructed of circularly rolled sheets, andconsequently the drum inside diameter is not absolutely uniform. Byvirtue of mounting the grinding apparatus i in the flexible bearings m,however, the grinding tape 0 nevertheless can adapt itself to thesedeviations from the theoretical diameter.

The pressure of the grinding apparatus on the drum wall acts downwardlyand is accommodated by the rolls r of a drum-rotating device s of aconstruction known per se, which is driven by variable ratio gearing t,whereby the rate of grinding may also be varied.

A suction device it which is only schematically shown, serves thepurpose of rapidly removing the metal dust produced by the grindingoperation.

What we claim is:

Apparatus for grinding the inside walls of cylindrical containerscomprising an external support for the container to be ground, a frameadjacent said support, external vertical guides on said frame, a slidemounted on said guides, a motor and gearing mounted on said slide, across-arm extending on one side of said slide into the cylindricalcontainer to be ground and mounted on said slide for limited reciprocalmovement by said motor and gearing, a cantilever arm mounted on the endof said cross-arm projecting into the cylindrical container, saidcantilever arm and cross-arm having parallel axes, means on saidcross-arm for adjusting the distance between the axes of said cantileverarm and said cross-arm, resilient bearings on said cantilever arm, andan internal grinding apparatus and a motor therefor mounted in saidresilient bearings on said cantilever arm, said grinding apparatuscomprising an endless grinding belt.

References Cited in the file of this patent UNITED STATES PATENTS2,279,782 Fowler Apr. 14, 1942 2,445,391 Elmes et a1. July 20, 19482,470,221 Mott May 17, 1949 2,768,481 Thomasco Oct. 30, 1956

